During the last year, a large amount of effort was invested in reviewing neutron guide concepts at many facilities for the ESS project. The goal in this review was to attempt to converge at a concept that offers the maximum return on investment in neutron guide systems, in light of recent developments of high m value supermirrors, advanced geometries, and precise manufacturing techniques. In so doing, a common understanding of numerous optical effects has been reached, which we will summarise. Moreover, these allow us to begin to define a standard geometry guide, which would serve the majority of neutron instruments with low cost and high efficiency. On the other hand, there remain a number of instruments that require more specialised optics, and we will discuss the current state of the art for those examples within the context of this work.